Effect of psycho-physical stress on gene expression leading to orofacial and dental abnormalities by modulation of the NF- B signaling pathway in rat embryo

Abstract

Prenatal stress has a substantial effect on physical and psychological development of fetus. This study was carried out to assess the effect of prenatal restraint stress on NF-B signaling pathway and related expression ofBMP2 and Runx2 proteins in rat offspring. We also explored the effect of gestational restraint stress on jaw and dental dimensions. Materials and methods: One hundred and twenty pregnant Wistar rats were divided into the experimental (SG) and control (CG) groups. The rats in SG were exposed to restraint stress during the pregnancy period. The animals of CG were not exposed to stress. Each group comprised three subgroups of G14 and G21 in which the rats were sacrificed in day 14 and 21 of pregnancy respectively, and G80 in which the offspring were killed 80 days after delivery. Runx2, BMP2 and NF-B (including IB, P50 and P65) genes’ expression were assessed using real-time PCR at G14 and G21. The dental and jaw measurements were obtained at G80. Results:The results showed that Runx2 gene expression in 21-day-old embryos was significantly lower in SG compared to CG (p<0.001). The expression of IB, P50 and P65 genes at day 21 of pregnancy were significantly higher in SG than in CG (p0.01). BMP2 gene expression was not significantly different between the two groups at G21. Maxillary and mandibular measurements at G80 were also significantly smaller in SG (p<0.001). The dental dimensions of 80-day-old offspring were smaller in SG than in CG. Conclusion: In conclusion, prenatal restraint stress can result in smaller jaws and teeth, probably, through the up-regulation of NF-B signaling pathway and down-regulation ofBMP2 and Runx2 genes’ expression.